RU2672737C2 - Method and device for liquid/solid separation such as dewatering particulate solids and agitation leaching - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention relates to a device and a method for separating liquid from solid particles and can be used to dry solid particles and extract precious metals from ore in a leaching process. Device includes a tank for solid particles and liquid in the form of a slurry, an inlet into the interior of the tank for feeding solid particles and liquids, a fluid outlet, a stirrer suspended inside the tank, a filter extending upwards through the filter layer area. Method for separating liquid from solid particles includes steps of feeding solid particles and liquid into the tank, mixing the solid particles and the liquid to form a slurry, forming a filter layer, moving the liquid through the filter layer, draining the liquid from solid particles and removing the solid particles.EFFECT: effective separation of liquid from solid particles is provided.11 cl, 6 dwg, 2 tbl, 3 ex

Description

Cross reference to related application

[0001] This application claims benefits in accordance with 35 U.S.C. §119 (e), US Provisional Application Serial Number 61 / 883,411, filed September 27, 2013, entitled “Mechanical Stirring Leaching Method and Device”, which is incorporated herein by reference.

Technical field

[0002] The present invention relates to methods and apparatus for liquid / solid separation for use in applications such as dehydration of solid particles, and the recovery of precious metals from ore in a leaching process. In one aspect, the invention relates to methods for leaching metals, such as gold from gold-bearing materials, with mechanical stirring.

State of the art

[0003] Separating solid particles from a liquid has many uses. They include dewatering of sludge in the form of particles and separation of liquid from solid particles in the leaching process. The leaching of components from mineral materials in the form of particles is practiced using a variety of materials and equipment. Leaching procedures are especially useful for the extraction of metals from mineral ores in the form of particles such as gold, silver, copper and uranium ores. The dominant process for recovering such metals from ores is leaching with leaching agents. Typical leaching methods have a number of drawbacks, in particular, the need to either finely grind the ore for continuous leaching with mechanical stirring, or to use batch leaching methods on large material.

[0004] Capacitive leaching is usually a continuous process, while tank leaching is performed in a batch mode. Capacitive leaching is commonly used to extract gold and silver from ores. Capacitive leaching differs from tank leaching in that, in capacitive leaching, the material is ground finely enough to form a suspension that can flow due to gravity or when the pump is running, while in tank leaching, usually large material is placed in a leach vat. Tanks in a capacitive leaching process are typically equipped with agitators in order to keep solids in suspension in containers and to improve solid-liquid-gas contact. Partitions can be provided to increase mixing efficiency and to prevent centrifugation of suspensions in cylindrical tanks. Vats in vat leaching generally do not contain such equipment. In case of capacitive leaching, the suspension is mixed, while in case of tank leaching, solid particles remain motionless in the tank and the solution is moved, therefore, as a rule, the residence time required for tank leaching is longer than the residence time for capacitive leaching to achieve the same percent recovery of precious material being leached.

[0005] Capacitive and tank leaching, both include placing the ore, after being reduced in size and classification, in a tank or vat under operating environmental conditions containing a leach solution and allowing precious materials to leach out of the ore into the solution. With capacitive leaching, classified solids are already mixed with water to form a suspension, and this is pumped into the tank. Leachates are added to containers to achieve a leach reaction. In a continuous system, the suspension will then either flow from one tank to another, or be pumped to the next tank. Ultimately, the saturated solution is separated from the solid particles using a specific form of the liquid / solid separation process, and the solution proceeds to the next extraction step. During vat leaching, solid particles are loaded into the vat and, as soon as the vat is filled, it is poured with a leaching solution. The solution drains from the tank and is either returned to the vat or pumped to the next stage of the extraction process.

[0006] Factors that affect the recovery efficiency are:

I) residence time - time spent in the leaching system with solid particles. It is calculated as the total capacity of the leach vat (s) divided by the volumetric throughput of the solid / liquid suspension.

II) Particle size - the ore is crushed to a size that leaves the required material unprotected from the effects of the leaching agent. With capacitive leaching, this should be a size that can be fully mixed and suspended by the mixer. In tank leaching, this is the size that is most economically feasible, which balances the recovery and increased cost of processing the material.

III) Density of the suspension — The density of the suspension (percentage of solid particles) determines the residence time. The deposition rate and viscosity of the suspension are functions of the density of the suspension. Viscosity, in turn, controls gaseous mass transfer and leach rate.

IV) Dissolved gas — A gas, typically oxygen, can be introduced into the solution to obtain the desired levels of dissolved gas.

VI) Reagents are added and an appropriate amount of reagents is maintained throughout the leach circuit to maximize metal recovery.

V) Temperature affects the kinetics of the reaction.

VI) Leaching inhibitory elements, such as minerals, absorbing leaching agents, or carbonaceous materials.

[0007] Generally accepted knowledge suggests that the maximum particle size for leaching with mechanical stirring should be significantly less than 1 mm in diameter to allow maximum extraction at an acceptable residence time, as well as allowing completely uniform mixing. Gold leaching through CO2 capture using finely divided particles allows for carbon separation. Such a small particle size requires costly grinding.

[0008] The foregoing examples and limitations associated with them are intended to be illustrative and not exclusive. Other limitations of the prior art will become apparent to those skilled in the art after reading the description and studying the drawings.

SUMMARY OF THE INVENTION

[0009] The following embodiments and their aspects are described and illustrated in combination with systems, tools and methods that are intended to be an example and illustration and not limited in scope. In various embodiments, one or more of the above problems has been reduced or eliminated, while other embodiments are directed to other improvements.

[00010] The present invention, therefore, provides a liquid / solid separation method and device. According to one aspect, the invention provides a method and apparatus for dewatering particulate matter.

[00011] Thus, a device for separating a liquid from solid particles is provided, comprising:

I) a container for containing solid particles and liquid in the form of a suspension;

Ii) an inlet for introducing solid particles and liquid into the container;

Iii) a fluid outlet passage in communication with the inside of the container;

Iv) an agitator suspended inside the vessel to form a suspension of particles in said liquid;

V) a container having a lower section for forming a filter layer in order to drain the liquid from the container; and

VI) a filter passing upward through the region of the filtering layer and communicating with the outlet passage in order to receive at its upper end a liquid stream from the above-mentioned lower section, which is conducted downward to flow out through the section with the filtering layer into the outlet passage or directly into the outlet passage. The filter may be a needle filter or a well filter.

[00012] In accordance with another aspect, the present invention further provides a method for separating a liquid from solid particles, comprising the steps of:

I) providing a device, as described above, for dehydration of solid particles, containing:

Ii) the introduction of solid particles and liquid into the container;

III) mixing of solid particles and liquid to form a suspension;

Iv) stopping the stirring to allow the suspension to settle, thereby forming an inhomogeneous filter layer for draining the liquid from the container;

V) the use of a filter to transfer fluid from above the filter layer into the filter layer, or directly into the outlet passage;

VI) removal of liquid from solid particles; and

VII) removal of solid particles.

The amount of coarse solids can be added to the solids and liquids in the container where coarse solids are suitable for forming a filter layer. The mixer can be a variable speed mixer and mixing is slowed down to the precipitation stage.

[00013] The device can be used to leach with mechanical stirring mineral-containing or metal-containing particles, a significant portion of which may be 1 mm in diameter or more, in which the bulk material contains gold, silver, copper or uranium, and the liquid contains leachate concentrations.

[00014] The method can be used to leach with mechanical stirring mineral-containing or metal-containing particles, a significant portion of which may be 1 mm in diameter or more, in which the bulk material contains gold, silver, copper or uranium, and the liquid contains leachate concentrations.

[00015] In addition to the illustrative aspects and embodiments described above, additional aspects and embodiments will become apparent when referring to the drawings and when studying the following detailed description.

Brief Description of the Drawings

[00016] Illustrative embodiments are shown in the drawings. It is intended that the embodiments and features disclosed herein should be considered as illustrative rather than restrictive.

[00017] FIG. 1 - the left side of the perspective view of the installation for implementing the method according to the invention.

[00018] FIG. 2 is a right rear perspective view of the apparatus shown in FIG. one.

[00019] FIG. 3 is a side view of the apparatus shown in FIG. one.

[00020] FIG. 4 is a schematic view taken in cross section along line 4-4 of FIG. one.

[00021] FIG. 5 is a vertical cross-sectional view along line 4-4 of FIG. 1 leach tank.

[00022] FIG. 6 is a side view of a deposition and storage tank.

Description

[00023] In the following description, specific details are set forth in order to provide a better understanding to those skilled in the art. However, well-known elements may not be shown or described in detail in order to avoid unnecessary difficulty in understanding the disclosure. Accordingly, the description and drawings should be considered in an illustrative rather than restrictive sense.

[00024] Improvements in the methods and apparatus for the separation of liquid / solid are described below, which are used in dehydration of solid particles. Particularly useful applications are found in the extraction of precious metals from ore in the leaching process, and more specifically, in methods of leaching with mechanical stirring of metals, such as gold from gold-containing raw materials. The device uses split, diaphragm, perforated, perforated or mesh vertical tubes or pipes. One suitable form of such a tube or tube is also called a needle filter. These are vertical tubes or pipes, usually made of stainless steel or PVC, with a continuous set of holes, which can be a filter and / or mesh, which allow the flow of fluid into and along the central channel of the tube, but prevent particles that are larger than the selected diameter. They also share such features with pipe well filters. All of these devices will be referred to herein as interchangeable, such as needle filters, downhole filters, or more generally, filters.

Continuous Leaching with Mechanical Stirring

[00025] The applicant has developed a new method and device, which in one application, for leaching by cyanidation with mechanical stirring of gold-bearing particles, may include the following features:

- leaching of particles up to about 2 mm in size or more;

- high concentrations of cyanide, up to 10 times higher than normal concentrations;

- variable mixing speed;

- the formation of a filter layer to drain the cyanide / gold solution from the tank; and

- the use of a vertical filter, such as a needle filter, to deal with the formation of an impermeable film on the upper surface of the filter layer.

[00026] Generally accepted knowledge suggests that the maximum particle size for leaching with mechanical stirring should be significantly less than 1 mm. The applicant has developed a new method that can process larger particles - 2 mm or more - and process them more quickly. The leaching process is intense, since the concentration of cyanide is about 10 times higher than the usual concentration. A variable speed motor 41 for agitator 40 can be used operating at the lowest possible speed, which causes large particles to move at the bottom of the tank, resulting in significantly less wear on components than with high-speed uniform mixing. The mixer then slows down so that the heavy particles sink to the bottom of the vessel and settle, eventually forming an inhomogeneous filter layer with large particles at the bottom and smaller particles at the top. The stirrer blades remain above the bed in a liquid suspension. This heterogeneous layer serves as a filter to drain the cyanide / gold solution from the vessel.

[00027] Referring to FIG. 1, 2 and 6, a gold-containing crushed concentrated suspension, for example, extracted from a centrifugal concentrator, is fed into the sedimentation and storage capacity of raw materials 10 through a supply pipe 17. The solids are allowed to settle and the excess water is drained from the concentrate, for example, using an outlet valve 15 The flow pipe 13 can redirect the drain from the tank 10. The water circulation line can be installed at 12. At selected intervals, when the tank 10 is full of slurry that has been dehydrated to the desired degree, the exhaust valve 14 is open yvaetsya, and the concentrate is fed by a pump from the tank 10 through the pipe 16 in the form of suspensions 11 (Fig. 4) in a substantially empty container 20 for leaching.

[00028] The cylindrical leach tank 20, as shown in FIG. 5, has a cover 21, vertical sides 25 and a bottom 23. The supply pipe 62 carries the initial concentrated suspension from the pipe 16 to the channel 63, and then into the vessel 20. The supply pipe 62 also carries a cyanide solution into the vessel 20. The pipe 64 is one of several adjacent pipes through which reagents can be added to the tank 20. A pipe for adding reagents (not shown) and a supply pipe 18 for recirculation are also included in the tank 20 to the channel 63 adjacent to the pipe 62. A stirrer 40, driven by a variable motor speed 41, suspend to the frame 43, it has blades 42 rotated on the shaft 45. The level sensor 70 detects the level of solids or cyanide solution in the vessel 20. The hydrogen cyanide sensor 72 detects the presence of hydrogen cyanide in the vessel 20 as a safety measure, since the gas produced as part of the leaching process , can be explosive and highly toxic to humans when present in excess. Partitions 28 are attached to and extend from wall 25 to reduce rotation of the suspension.

[00029] The needle filter 60 is screwed into the bottom 23 of the container 20 and connected through valves to the pipe system 52, which removes the saturated solution. The tail outlet 30 communicates with the tail outlet pipe and is opened or closed by a valve actuator 74, or, alternatively, manually controlled 76. Bathtubs or static filters 48 are fixed to the lower part 23 of the container 20 and are connected through filters 49 to the inside of the container 20 and through a pipe 52 for discharging a saturated solution. The oxygen supply 66 introduces oxygen into the vessel 20.

[00030] The leach tank 20 is filled with concentrate until the level of solid particles in the suspension is slightly lower than the blades 42 of the mixer 40. A cyanide solution, such as sodium cyanide, with a high concentration of cyanide, is 10 times higher than the usual concentration during leaching, added to the tank 20 through the pipe 16 and the exhaust pipe 62, to level 22, providing a ratio of solid particles to liquid of about 30-40%. Preferably, finely divided oxygen bubbles are added directly to the solution through the inlet 66 and dissolved, providing at least 10 ppm of dissolved oxygen in the solution to improve the reaction. The cover 21 provides overpressure to create it in the vessel 20 when oxygen is introduced in order to increase the dissolution of oxygen in the solution.

[00031] The stirrer 40 begins to rotate for several hours, typically up to 18-20, depending on the characteristics of the ore. Preferably, when the blades 42, as shown in FIG. 5 are designed to cause shear to move through the solution, which aids leaching. For example, the blades 42 may be triangular in cross section, at an angle downward, with the sharp end of the triangle forming the attacking edge of the blade. The baffle 28 reduces the rotation of the suspension in order to increase the mixing effect. About 5 minutes before the stirrer stops, the coagulant can be added to the solution and mixed for a short period, such as 2 minutes, followed by the addition of a flocculant, which is stirred for 3 minutes. The stirrer is then slowed and stopped for several minutes, and the solids are allowed to settle. Heavier particles settle most quickly to form a filter layer 50, followed by lighter particles. Typical deposition time is 30 minutes.

[00032] Since the smallest particles settle in the suspension, a thin film forms at 54 above the layer 50. To allow the liquid to easily pass through the layer 50, the filters or filters 60 extend over the film of small particles that covers the filter layer at 54. A suitable type of needle filter, for example, has an internal diameter of about 2 inches, about 3 inches in length, with grooves from 7 / 1,000 to 10 / 1,000 inches, like a Johnson-type frame-filter. One size that was used successfully was the size of a 2P sand-cut tube, a stainless steel wire filter model 304 with 10 / 1,000 inch 60 grooves, model number 936 can also be used. Well filters can also be used. Fluid flows through the needle filter and into the layer 50 when the valve connecting the filter 60 to the pipe 52 (not shown) is closed and flows directly from the pipe 52 when it is open.

[00033] The needle filters 60 are first cleaned by backwashing using a vacuum return pump 56, and then the recirculation fluid flows through the filters through the vacuum pump 56 with the needle filter valves open, the central passage through the screened baths 48 is closed and the recirculation pipe 18 is open.

After the filters are cleaned, after about 3 minutes of recirculation, the valves of the filters are closed and the saturated solution is drawn through the filters into the bed 50 and leaves the bottom of the screened baths 48 via the vacuum pump 56 into the exhaust pipe 52 and then, preferably, the saturated solution is recycled through the pipe 18 back to the upper part of the container 20 and through the needle filters 60, and the filter layer 50 for an additional short period of time, such as 5-6 minutes, to clean the solution until the purity escapes of the flow will not be sufficient for further processing. The purified saturated liquid can then be pumped directly by the vacuum pump 56 through the needle filters 60 by opening the valve connection into the pipe 52, or bypassing through the layer 50 and the bath 48 into the outlet pipe 52, and pumped into the storage tank to prepare for the electrolytic or other processing method.

[00034] As soon as the liquid from the vessel 20 is removed, the concentrated layer 50 is washed and the liquid is removed to recover any dissolved gold. This can be done first by adding dehydrated cyanide or water to the vessel 20, to or above the stirrer 40, if stirring is necessary, and draining the liquid through layer 50 into pipe 52. The cyanide is then removed from layer 50. This can be done by rinsing with clean water, which is discharged through pipe 52 to a different destination than a saturated solution or using other known methods of cyanide removal. The solids are then dried by adding water above the level of the stirrer 40, stirring for a short period, such as 5 minutes, and then allowing the suspended concentrate to flow by gravity through the outlet 30.

Example 1 - leaching of gold by cyanidation

[00035] A successful pilot plant, as described above, was created to test the invention with the goal of leaching gold by cyanidation from ore gravel concentrate. The storage tank for raw materials 10 had a volume of 2.3 m ³ . The leach tank 20 had a volume of 8 m ³ , the volume of which can be changed depending on the throughput. The holes in the needle filters 60 and bottom filters 49 were 25 microns in size. The rotation speed of the mixer 40 was set at a level of from 100 to 120 revolutions per minute. The settling time with stop of the stirrer 40 was 30 minutes to precipitate particles smaller than 75 microns.

[00036] The pilot plant provided successful gold leaching with a maximum leaching time of 18 to 20 hours on a 24-hour duty cycle. The maximum daily throughput was 4 tons per day of particulate matter, usually 3 tons per day. The particle size of the raw materials was a maximum of 6 mm, usually 2 mm. This is the normal particle size for a Falcon concentrator concentrate. The concentration of gold in solid particles of raw materials ranged from about 800 grams / ton to 900 grams / ton. A concentration of cyanide in the leach solution of from 10,000 ppm to about 25,000 ppm, and typically 20,000 ppm, has been used. The concentration is selected depending on the properties of the ore. The concentration of solids in the leach tank 20 was a maximum of 40% by weight, and usually with 30% by weight. Reagents were used, with NaCN used to set the concentration of CN (cyanide), with a pH control provided by lime or NaOH, and with dissolved oxygen (O ^2- ) control by bubbling gaseous oxygen or air. Four needle filters and four screened baths 48 were used to drain the liquid, although a smaller number would also work, only two needle filters and one screened bath 48.

[00037] The test results showed an extraction efficiency of about 99.3%, for example, with an initial grade of 900 g / ton and tailings of about 6 grams per ton of gold.

[00038] The disclosed method, in relation to cyanidation leaching, produces a cleaner effluent through a graduated sand filter. This is an advantage for the electrolytic process that occurs after leaching. This provides better liquid / solid separation. Competing technologies reject the fine fraction before leaching begins or have an ineffective and incomplete way to separate liquid from solid particles. The current system is easily scalable, both up and down, therefore it is cost-effective both on a small scale and on a large scale, unlike competing systems. This is absolutely acceptable for an industry based on traditional mixing technology, which is widely used and understood in gold mining and uses widely available components.

Particulate dehydration

[00039] It was found that, as a rule, the same device and methodology used for cyanidation leaching, as described above, can be used, in a more general sense, for dehydration of many types of particulate matter, where such particulate matter could not be free to flow differently. While the method can be used with a suspension of only finely ground materials, it has been found to be particularly effective when a predetermined amount of a larger, heavier ground material is also added to form a filter layer.

[00040] The following tests set forth in Examples 2 and 3 were performed in laboratory sizes, with a reduced version of the device used in Example 1 and shown in FIG. 5. The liquid / solid separation method was essentially the same. When coarse filter bed material was added to the slurry, mixed-sized silica sand particles were used as the bed material. Such large particles were carefully selected in the range from 2 mm to 4 mm in diameter and they could be different fractions depending on the characteristics of the raw material.

[00041] Since in the leaching method described above, solid particles, to be dehydrated, with or without a specifying filter layer material in accordance with a particular test, were added to the container 20 together with the required amount of water, with a surface liquid level above mixers. The stirrer 40 began to rotate for several minutes at low speed (40-60 Hz or with a rotation speed of 800 to 1200 rpm), until the solid particles became in suspension. Shortly before the stirrer was stopped, a flocculant was added to the mixture. The type of flocculant, such as a polymer flocculant, is determined by the type of particulate matter to be agglomerated. Then the mixer 40 was slowed down and stopped after four minutes, and the solids were allowed to settle. Heavier particles settle most quickly to form a filter layer 50, followed by lighter particles. Therefore, if larger, heavier particles were added as the master layer, then they settle to form the filter layer first. As in the leaching method described above, when the smallest particles are deposited from the suspension, a thin film forms at 54 above layer 50. To allow fluid to continue to flow through layer 50, the filters or filters 60 extend through the fine film that covers the filter layer at 54.

[00042] The needle filters are then cleaned by backwashing with the help of a vacuum pump 56, and then the recirculation fluid flows down through the needle filters using a vacuum pump 56 with open needle filter valves and a closed central passage through the screened bathtub 48. After the needle filters are cleaned, after 3 minutes of recirculation, the needle filter valves are closed and the liquid is discharged through the needle filters into the layer 50 and from the bottom of the screened bathtubs 48 by means of a vacuum pump 56. The initially filtered liquid for thereby being recycled by sending it back above the filter layer to the upper part of the container 20, and then through the needle filters 60 and the filter layer 50 for an additional short period of time, such as 5-6 minutes, to clean the liquid until the purity of the effluent is not will be sufficient for additional processing. The liquid can then be drawn directly using the vacuum pump 56 through the needle filters 60 by opening the valve connection of the needle filters into the pipe 52 or bypassing, through the layer 50 and the bath 48, into the outlet pipe 52, and transferred to a storage tank. In the case of a dehydration process, the dehydrated solids are then physically removed by mechanical means from the tank for transportation to other places. For example, if large-scale tanks are used, access to the inside of the tank can be achieved using a manned compact tracked loader or front-end loader to physically remove and transport dehydrated solid particles. Access to the container can be, for example, through a movable sealed door.

Example 2 - Fine mineral raw materials

[00043] Effective dewatering of fine minerals has been achieved using prepared material with a large mineral layer in a vessel with a stirrer. Two tests were carried out, in one of which no material with a large layer was added, and in the other 4 kg of material with a large layer was added to the container. The fine minerals used were the remainder of the tailings of the concentration vibrating table leaching cyanidation. It was a finely dispersed particle size distribution, finely selected so that all particles were less than 1 mm in diameter and it was P80 at 370 microns (80% of the material passed the filter at 370 microns). The following parameters were obtained and measured, where “feed weight” is the total weight of solid particles (including material with a specifying filter layer), “layer material weight (%)” is a percentage by weight of the layer material to the total feed weight, “ flocculant additive (g) ”is the amount in grams of added flocculant,“ pulp density (%) ”is the weight percent of solids to the total weight of the suspension,“ settling time ”is the time in minutes after stopping mixing and before draining, and“ drain time 'is the time in minutes from the beginning of the discharge a time when there is no standing water on the bed and no more fluid flowing through wellpoints.

Fine mineral raw materials Test number one 2 Feed Weight (kg) 6 10 Layer material weight (%) 0 40 Flocculant supplement (g) 25 25 Pulp Density (%) 40 40 Precipitation Time (min) fifteen fifteen Drain time (min) > 300 45

[00044] This test showed that without material with a large layer, 6 kg of fine mineral raw materials took> 300 minutes to naturally dehydrate, although there was a drain at the bottom of the tank. When 4 kg of material with a large layer was added to the tank, the total dehydration time (so that no standing water was present above the material) was reduced to 45 minutes.

Example 3 - Dehydration of organic matter (soil)

[00045] Effective dehydration of organic matter was also achieved using prepared material with a large mineral layer in a stirred tank. Two tests were carried out, in one of which no material with a large layer was added, in the other 5 kg of material with a large layer were added to the container. Organic matter was standard garden peat. One cycle of stirring, precipitation and evacuation was used. The following parameters were measured and obtained.

Organic matter (soil) Test number one 2 Feed Weight (kg) 2,5 5 Layer material weight (%) 0 fifty Flocculant supplement (g) thirty thirty Pulp Density (%) 25 25 Precipitation Time (min) 45 45 Drain time (min) 300 fifteen

[00046] This test showed that without material with a large layer, 2.5 kg of soil raw materials took 300 minutes to naturally dehydrate, although there was a drain at the bottom of the tank. When 5 kg of material with a large layer were added to the tank, the total dehydration time (so that no standing water was present above the material) was reduced to 15 minutes.

[00047] While a number of exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain modifications, permutations, additions, and sub-combinations thereof. Thus, it is contemplated that the invention should be interpreted as including all such modifications, permutations, additions, and sub-combinations, as they fall within their true nature and scope.

Claims (32)

1. A device for separating liquid from solid particles, including: I) a container for containing solid particles and liquid in the form of a suspension; Ii) an inlet into the interior of the vessel for introducing solid particles and liquid into the vessel; Iii) a fluid outlet passage in communication with the inside of the container; Iv) an agitator suspended inside the vessel to form a suspension of said particles in said liquid; V) said container having a zone of a filter layer in its lower part for forming a filter layer from the deposition of solid particles from a suspension through which liquid exits the container; and VI) a filter extending upward through the zone of the filter layer, the filter having a hollow inner region and having on its upper surface a plurality of holes to the hollow inner region along its length above and below said filtration zone, and communicating with an outlet passage for receiving at its upper end liquid flow from above the zone of the filter layer, which is conducted down to flow through the filter layer into the liquid outlet or directly into the liquid outlet. 2. The device according to claim 1, wherein said filter is a needle filter or a downhole filter. 3. The device according to claim 1, wherein said mixer is a variable speed mixer. 4. The device according to claim 1, additionally containing: Vii) a passage for removing solid particles from said container after liquid separation. 5. The device according to claim 1, additionally containing: VIII) a pump for removing liquid through said liquid outlet passage. 6. A method of separating liquid from solid particles, comprising the following stages: I) providing a device for dehydration of solid particles containing: a) a container for containing solid particles and liquid in the form of a suspension; b) an inlet to the interior of the vessel for introducing solid particles and liquid into the vessel; c) a fluid outlet passage in communication with the inside of the container; d) an agitator suspended inside a container to form a suspension of solid particles in a liquid; e) said container having a zone of a filter layer in its lower part for forming a filter layer from the deposition of solid particles from a suspension through which the liquid exits the container in order to drain the liquid from the container; and f) a filter that extends upward through the area of the filter layer and communicates with the liquid outlet for receiving at its upper end a liquid stream from the top of the lower section, which is held down to flow through the zone of the filter layer into the liquid outlet or directly to the outlet passage for liquids. Ii) the introduction of solid particles and liquid into the container; III) mixing solid particles and liquids to form a suspension; Iv) stopping said stirring to allow said suspension to settle, thereby forming a filter layer for draining the liquid from the container; V) using a filter to move the liquid from above the filter layer into the filter layer or directly into said outlet passage; VI) the removal of liquid from solid particles; and VII) removal of solid particles. 7. The method according to claim 6, in which many large solid particles are added to said solid particles and liquids in said container, said large solid particles being suitable for forming a filter layer. 8. The method according to claim 6 or 7, wherein said filter is a needle filter or a downhole filter. 9. The method according to claim 6, 7, wherein said mixer is a variable speed mixer and said mixing is slowed down before said deposition step. 10. The device according to any one of claims 1, 2, used for leaching with stirring mineral-containing or metal-containing particles, a significant part of which is 1 mm in diameter or more, and the said particulate material contains gold, silver, copper or uranium and the liquid contains leach concentration. 11. The method according to any one of claims 6, 7, used for leaching with stirring mineral-containing or metal-containing particles, a significant portion of which is 1 mm in diameter or more, said material in the form of particles containing gold, silver, copper or uranium and the aforementioned the liquid contains leach concentration.

Images